What does 'intentionality' mean in philosophy?

It refers to the aboutness or directedness of mental states, not to intention in the everyday sense of planning to do something.

Intentionality and Mental Content

Definition

Intentionality is the property of mental states whereby they are directed at, about, or represent objects and states of affairs; mental content is the specific representational character that fixes what a state is about.

Scope

This area covers the aboutness of mental states, naturalistic theories of how mental states come to have content, the internalism-externalism debate over whether content depends on the environment, the computational theory of mind, and the structure of propositional attitudes such as belief and desire.

Sub-topics

Core questions

How can purely physical states be about anything?
What naturalistic relation makes a state represent what it represents?
Is mental content fixed by what is inside the head or by the environment?
How are propositional attitudes such as belief and desire structured?

Key concepts

aboutness
mental representation
naturalized semantics
content externalism
language of thought
propositional attitude

Key theories

Intentionality as the mark of the mental: Mental phenomena are distinguished by their directedness upon an object, a feature Brentano took to be absent from the purely physical.
Informational and causal theories of content: A state's content is fixed by the information it carries or the states of affairs that reliably cause it, providing a naturalistic basis for representation.

History

Brentano (1874) reintroduced intentionality as the mark of the mental. Twentieth-century philosophers sought to naturalize it: Dretske's informational semantics and Fodor's asymmetric-dependence theory aimed to ground content in physical relations, while Putnam's (1975) Twin Earth argument launched the externalist turn that reshaped debates about where content is fixed.

Debates

Naturalizing content: Whether the aboutness of mental states can be explained in non-intentional, physical terms, and which relation does the work.
Where content is fixed: Whether the content of a thought depends only on the subject's internal states or also on the external environment.

Key figures

Franz Brentano
Fred Dretske
Hilary Putnam
Jerry Fodor

Seminal works

brentano1874
putnam1975
dretske1981
fodor1987

Frequently asked questions

What does 'intentionality' mean in philosophy?: It refers to the aboutness or directedness of mental states, not to intention in the everyday sense of planning to do something.